Recently, interest on global environment conservation and effective energy use has been growing in various fields to prevent global warming, fossil fuel depletion, environmental contamination, and the like, and thus various kinds of environmental technologies have been researched.
In such environmental technologies, it is important to understand a combustion structure of a combustion phenomenon in an engine, a burner, or the like, and transitional behavior thereof in detail. Recently, measurement technologies utilizing a semiconductor laser absorption spectroscopy have been developed as means for measuring temperature and concentration distributions of combustion gas in a highly responsive and temporally sequential manner.
Typically, an absorption spectroscopy is a measurement method utilizing property that gas molecules absorb infrared light having a wavelength unique to a chemical species, and temperature and concentration dependency of the amount of absorption. The concentration and temperature of an absorption medium (target gas) having a uniform optical path length can be measured by obtaining the ratio (Iλ/Iλ0) of the intensity (Iλ0) of incident light to the intensity of transmitted light (Iλ) having passed through the target gas.
The technology disclosed in Patent Literature 1 is a technology of detecting properties (concentration and temperature) of measurement target gas by the absorption method using a semiconductor laser.